(let ([f (lambda x x)]) (f))
=> ()
(let ([f (lambda x x)]) (f 'a))
=> (a)
(let ([f (lambda x x)]) (f 'a 'b))
=> (a b)
(let ([f (lambda x x)]) (f 'a 'b 'c))
=> (a b c)
(let ([f (lambda x x)]) (f 'a 'b 'c 'd))
=> (a b c d)
(let ([f (lambda (x . rest) (vector x rest))]) (f))
=> 
(let ([f (lambda (x . rest) (vector x rest))]) (f 'a))
=> #(a ())
(let ([f (lambda (x . rest) (vector x rest))]) (f 'a 'b))
=> #(a (b))
(let ([f (lambda (x . rest) (vector x rest))]) (f 'a 'b 'c))
=> #(a (b c))
(let ([f (lambda (x . rest) (vector x rest))]) (f 'a 'b 'c 'd))
=> #(a (b c d))
(let ([f (lambda (x y . rest) (vector x y rest))]) (f))
=> 
(let ([f (lambda (x y . rest) (vector x y rest))]) (f 'a))
=> 
(let ([f (lambda (x y . rest) (vector x y rest))]) (f 'a 'b))
=> #(a b ())
(let ([f (lambda (x y . rest) (vector x y rest))]) (f 'a 'b 'c))
=> #(a b (c))
(let ([f (lambda (x y . rest) (vector x y rest))]) (f 'a 'b 'c 'd))
=> #(a b (c d))